KVM: Cache pdptrs
Instead of reloading the pdptrs on every entry and exit (vmcs writes on vmx,
guest memory access on svm) extract them on demand.
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index 1ff819d..7bcc5b6 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -29,4 +29,13 @@
kvm_register_write(vcpu, VCPU_REGS_RIP, val);
}
+static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index)
+{
+ if (!test_bit(VCPU_EXREG_PDPTR,
+ (unsigned long *)&vcpu->arch.regs_avail))
+ kvm_x86_ops->cache_reg(vcpu, VCPU_EXREG_PDPTR);
+
+ return vcpu->arch.pdptrs[index];
+}
+
#endif
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 0ef5bb2..8ee67e3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -18,6 +18,7 @@
*/
#include "mmu.h"
+#include "kvm_cache_regs.h"
#include <linux/kvm_host.h>
#include <linux/types.h>
@@ -1954,6 +1955,7 @@
gfn_t root_gfn;
struct kvm_mmu_page *sp;
int direct = 0;
+ u64 pdptr;
root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
@@ -1981,11 +1983,12 @@
ASSERT(!VALID_PAGE(root));
if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
- if (!is_present_pte(vcpu->arch.pdptrs[i])) {
+ pdptr = kvm_pdptr_read(vcpu, i);
+ if (!is_present_pte(pdptr)) {
vcpu->arch.mmu.pae_root[i] = 0;
continue;
}
- root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
+ root_gfn = pdptr >> PAGE_SHIFT;
} else if (vcpu->arch.mmu.root_level == 0)
root_gfn = 0;
if (mmu_check_root(vcpu, root_gfn))
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 67785f6..4cb1dbf 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -131,7 +131,7 @@
pte = vcpu->arch.cr3;
#if PTTYPE == 64
if (!is_long_mode(vcpu)) {
- pte = vcpu->arch.pdptrs[(addr >> 30) & 3];
+ pte = kvm_pdptr_read(vcpu, (addr >> 30) & 3);
if (!is_present_pte(pte))
goto not_present;
--walker->level;
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 522e695..7749b06 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -777,6 +777,18 @@
to_svm(vcpu)->vmcb->save.rflags = rflags;
}
+static void svm_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
+{
+ switch (reg) {
+ case VCPU_EXREG_PDPTR:
+ BUG_ON(!npt_enabled);
+ load_pdptrs(vcpu, vcpu->arch.cr3);
+ break;
+ default:
+ BUG();
+ }
+}
+
static void svm_set_vintr(struct vcpu_svm *svm)
{
svm->vmcb->control.intercept |= 1ULL << INTERCEPT_VINTR;
@@ -2285,12 +2297,6 @@
}
vcpu->arch.cr0 = svm->vmcb->save.cr0;
vcpu->arch.cr3 = svm->vmcb->save.cr3;
- if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
- if (!load_pdptrs(vcpu, vcpu->arch.cr3)) {
- kvm_inject_gp(vcpu, 0);
- return 1;
- }
- }
if (mmu_reload) {
kvm_mmu_reset_context(vcpu);
kvm_mmu_load(vcpu);
@@ -2641,6 +2647,11 @@
svm->next_rip = 0;
+ if (npt_enabled) {
+ vcpu->arch.regs_avail &= ~(1 << VCPU_EXREG_PDPTR);
+ vcpu->arch.regs_dirty &= ~(1 << VCPU_EXREG_PDPTR);
+ }
+
svm_complete_interrupts(svm);
}
@@ -2749,6 +2760,7 @@
.set_gdt = svm_set_gdt,
.get_dr = svm_get_dr,
.set_dr = svm_set_dr,
+ .cache_reg = svm_cache_reg,
.get_rflags = svm_get_rflags,
.set_rflags = svm_set_rflags,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 752465f..d726dec 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -161,6 +161,8 @@
VMX_SEGMENT_FIELD(LDTR),
};
+static void ept_save_pdptrs(struct kvm_vcpu *vcpu);
+
/*
* Keep MSR_K6_STAR at the end, as setup_msrs() will try to optimize it
* away by decrementing the array size.
@@ -1047,6 +1049,10 @@
case VCPU_REGS_RIP:
vcpu->arch.regs[VCPU_REGS_RIP] = vmcs_readl(GUEST_RIP);
break;
+ case VCPU_EXREG_PDPTR:
+ if (enable_ept)
+ ept_save_pdptrs(vcpu);
+ break;
default:
break;
}
@@ -1546,6 +1552,10 @@
static void ept_load_pdptrs(struct kvm_vcpu *vcpu)
{
+ if (!test_bit(VCPU_EXREG_PDPTR,
+ (unsigned long *)&vcpu->arch.regs_dirty))
+ return;
+
if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
vmcs_write64(GUEST_PDPTR0, vcpu->arch.pdptrs[0]);
vmcs_write64(GUEST_PDPTR1, vcpu->arch.pdptrs[1]);
@@ -1562,6 +1572,11 @@
vcpu->arch.pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
vcpu->arch.pdptrs[3] = vmcs_read64(GUEST_PDPTR3);
}
+
+ __set_bit(VCPU_EXREG_PDPTR,
+ (unsigned long *)&vcpu->arch.regs_avail);
+ __set_bit(VCPU_EXREG_PDPTR,
+ (unsigned long *)&vcpu->arch.regs_dirty);
}
static void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
@@ -3255,10 +3270,8 @@
/* Access CR3 don't cause VMExit in paging mode, so we need
* to sync with guest real CR3. */
- if (enable_ept && is_paging(vcpu)) {
+ if (enable_ept && is_paging(vcpu))
vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
- ept_save_pdptrs(vcpu);
- }
if (unlikely(vmx->fail)) {
kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
@@ -3567,7 +3580,8 @@
#endif
);
- vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
+ vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP)
+ | (1 << VCPU_EXREG_PDPTR));
vcpu->arch.regs_dirty = 0;
get_debugreg(vcpu->arch.dr6, 6);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 75e9df0..2ad8c97 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -246,6 +246,10 @@
ret = 1;
memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs));
+ __set_bit(VCPU_EXREG_PDPTR,
+ (unsigned long *)&vcpu->arch.regs_avail);
+ __set_bit(VCPU_EXREG_PDPTR,
+ (unsigned long *)&vcpu->arch.regs_dirty);
out:
return ret;
@@ -261,6 +265,10 @@
if (is_long_mode(vcpu) || !is_pae(vcpu))
return false;
+ if (!test_bit(VCPU_EXREG_PDPTR,
+ (unsigned long *)&vcpu->arch.regs_avail))
+ return true;
+
r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte));
if (r < 0)
goto out;